System of electric welding.



D. H. WILSON. SYSTEM OF ELECTRIC WELDING.

APPLICATION FILED MAYI I9I5- RENEWED MAY I0, I9I6- 1,187,409. Patented June 13, 1916.

.U n a m. MVY 1% E QE M W a lIiw z WITNESSES "UNITED STATES- PATENT OFFICE.-

DAVID H. WILSON, PATERSON, NEW JERSEY.

SYSTEM OF ELECTRIC WELDING.

Application filed May 1, 1915,

. a metal electrode is composed of welding metal, the same being transferred across the arc to the work operated upon.

The object of my invention is the elimination of unnecessary initial resistance in the circuit and the general simplification of the apparatus.

It has been customary to perform electric welding operations with a current of such a potential that when the welding terminals are brought into contact rush of current causing metal if the circuit resistance to prevent the rush. Since such a resistance in the circuit interferes with the welding operations, ary to reduce the resistance or cut it out of a spattering of circuit as the arc is drawn.

My invention contemplates the use of a. current that is of sufii-' constant potential cient potential and volume to create an are but which is of such a low potential as to render an initial resistance in the circuit unnecessary. I have found by experience that the ordinary [resistance between the contacting terminals is suflicient to prevent a rush of current if the potential is kept down to a sufliciently low point. have disco ered, forexample,'that a current having a line voltage of 30 or 35 will not cause a detrimental rush of icurrent when the welding terminals are brought into contact so that my welding circuit has practically sufficiently heating no initial resistance other than ordinary circuit connections and the whole force of the current performs a useful function in the welding terminals to ermit the rapid drawing of the are. Since 1t is desirable afterdrawing the are to cut down theamperage of the current to the reof the particular piece or work the terminals from sticking t0gether",-a resistance is introduced into the circuit automatically upon establishing the flow of the welding current. Introducing the resistanceis preferably delayed however until after the are has Specification of Letters Patent.

have invented certain there would be awas not provided with a it has been custom- In the drawings: Figure been well drawn. Time controlled means are preferably employed to delay the introduction of the resistance until after the arc has been drawn.

My invention contemplates further a carbon pile capable of delicate and gradual regulation, for the purpose of even current at the. are.

It relates further to means average or normal may be adjusted at the will of the operator to provide a greater or smallerwelding current in accordance with the demands of: his work. a

It consists further in means to enable the operator to adjust the normal resistance of the pile from the place where his work is located.

It consists further in automatic stops to prevent the adjusting devicesof the carbon pile structure from rious limits. I

My invention also contains means to render regulation smoother and with less interby which the Patented J u'ne 13, 1916.

Serial No. 25,180. Renewed May 10, 1916. Serial No. 96,536.

resistance of the pile ference from the momentum of rapidly vibrating mechanical parts.

1 shows a view of the carbon pile, circuits and apparatiis designed to carry into -efiect the various objects named above. Fig. 2 is a section of Fig. 1 on line AA.

.In Fig. 1 is shown a piece of metal 1, constituting the workl' This piece of metal may be fractured as shown; and it may be ,part of a boiler or other piece of mechanism or .apparatus intended for repair. It may represent manufacturing process, or it may be any material to which my invention may be applied. This piece of metal 1, is connected through the conductor 2 to the source of welding current be the negative pole of a bipolar generator. The ,tool holder 4 is adapted to have secured to it a metal be of any suitable steel or alloy, in electrical a part intended for joining in a electrode 5, which may 3 which may, 'for example,

connection with the conductor'G, which may be a cable as indicated at 7. This conductor 6 is connected through the main regulating pile 8 and solenoid 9 to-the positive pole 10 of the generator. Y

The operation of the solenoid 8 is delayed and dampened by the dash-pot 11. To the core of the solenoid isosecured a rod 12 at the other end of which is fixed a plate 13 fittingfreely within the cylinder 14, forming the dash pot. The rod12 passes through the dash pot and increases the resistance up tact 18, he selects increasing the resistance of the pile.

the pile resistance purpose. It may preferably be adjusted by to the requirements of the welding are. It is thus apparent that when the electrode 5 isbrought into contact with the metal Work 1, the circuit established from the sources of electric current 3 and 10 over the circuits above described permits the passage first of an amount of current suflicient to establish the desired arc. The current is then reduced after the terminals become heated, being increased for the.

the operator (or anybody else) to supply a variable amount of current from say, 200 amperes, down to any amount, say 25, that may be desired by the operator. In'order that he may select the amount of current he desires, the operator is provided with a switch having an arm 17 adapted to come into contact with either one of the two contacts 18 or, 19. If the operator closes the circuit from the switch arm 17 to the-conthe desired normal resistance of the pile by operating the motor 20 in the following circuit: source of current 3, conductors 2 and 21, switch 17, contact 18, circuit closer 22, field coil 23 of the motor, the armature of the motor, conductor '24, to the terminal 10. This circuit causes the motorto rotate in such a direction as to advance springs 25 and 26 or other resilient means, to the left in the figure so that the rollers 27 and 28 travel tOWitI'ClgthG pile 8; the roller 27 traveling upon the fixed track 29. and the roller 28 upon the lever 30 (which is fulcrumed upon the fixed pivot 31 and engages the end 32 of the pile 8) so that the spring exerts a lessened compression upon the pile against the adjustable fixed abutment 33, thereby The full spring pressure may reducethe-resistance of the pile to substantially zero. As the pressure is counteracted or reduced, the resistance of the pile may be increased accordingly.

In this apparatus the motor 20 is provided with a pinion 34, engaging the gear wheels 35 and 36 causing the latter to travel as described. The springs 25 and 26 are fastened to the journals 37 and 38 of the rollers, tending to pull them toward each other. The up. er journal 37 is adapted to freely slide the slots 39 so that the roller is The object of this delay is to adapted to exert a fairly constant pressure upon the lever 30 anda varying pressure upon the pile. This lever is fulcrumed at 31 and presses against the post 40 of the end plate 41 of the pile. The plate exerts a pressure upon the pile, pressing the various disks of the pile into close engagement.

From this construction, it will be seen that the operator in closing the switch lever 17 to the contact 18 may cause the springs 25 and 26 to be carried along the lever 30, so that while its tension or pull is not greatly altered, its effect upon the pile is greatly altered. In this way the o erator is enabled to vary the amount 0 current supplied through the pile. If the operator leaves the switch 17 in engagement with the contact 18 too long, the lug 42 upon the carrier 43 engages an automatic circuit breaking lever 44 pivoted at 45 and properly located and switches it to the left against the compression spring 46 until the pressure of the spring is exerted in a direction tothe right of the pivot 45 thus throwing the lever over. This causes the arm '47 to engage lever 48 pivoted at 49 and causes it to break the circuit between the contacts 22, so that the motor 20 stops working.

hen the operator desires more current for his work, he shifts the lever 17 to the contact 19, thereby switching the current from the winding 23 of the field of the motor through the contacts 50 to the winding 51 of the fields of the motor, causing the motor to rotate in the opposite direction. The

motor now operates the traveler 43 to the right and causes the springs 25 and 26 to increase the pressure upon the pile, thereby reducing its resistance and increasing the current therethrough. To prevent the operator from damaging the construction by a too prolonged operation of the motor, the lug 42 engages the lever 52, thereby opening the pair of contacts 50 thereby opening the circuit of the motor and stopping its action. When the motor is reversed, the lug 42 engages the opposite arms of the levers 52 and 44, thereupon closing the circuits at 22 or 50 as the case may be. After the operator has adjusted the carbon pile in order to supply the tool with the average quantity of current desired for his Work, the main regulating solenoid 9 maintains the current substantially even at all times. i

there would result a detrimental local heating at the points of contact. The more uniform the contact is throughouathe area of the disks, the greater the amount of current which can pass through the disks without injurious heating and the less the consumption of the pile and the greater its life.' have found it desirable to employ a substantial pressure upon the disks as a minimum pressure, and to vary the same to a substantially high pressure."-

Since the momentum of the lever, solenoid, core and other mechanical parts during rapid osc'llation would cause them to overthrow, thereby increasing or decreasing the resistance too much for best results, some means is desirable to dampen their action to secure the more accurate regulation. The dash pot in performing this function adds a very desirable element to a weld ing panel. Y

The spring pressure upon the lever, which transfers the pressure to the carbon pile, may, if desired, be fifty pounds or more. As the spring travels away from or toward the fulcrum, the pressure upon the pile tends to be correspondingly varied. When the solenoid is energized, the pressure upon the disks is affected to an extent determined by the amount of current flowing through the solenoid winding. The pressure of the spring action upon the pile, however, is not entirely removed, since the solenoid action is never strong enough to overcome the full force of the traveling spring, I do not limit my invention to these specific pressures for various other ;pressures' may be employed, all depending upon the amount of current to be accommodated and the capacity of the pile. The object of the construction ust referred to is to keep the disks of the pile in such intimate or uniform contact throughout their surfaces as to prevent injurious heating. under all conditions of use. If the resistance at the-arc increases, due to the uncertainty of the operators manipulation of the tool, it causes a reduction'of the flow of current through the solenoid, which exerts'smaller pull upon its core resulting in a lighter pull upon the outer end of the lever, so that the carbon pile is subjected to more compression from the springs 25 and 26. When, however, the resistance of the welding arc-decreases, more current flows through the regulating. solenoid 8 thereby reducing the current supplied therethrough to the: tool. This regulating action takes place regardless of-the particular location of the springs 25- and 26 with relation to the lever 30. In this way the averagecurrent traversing, the welding arc ismainits heating effect. Whentained uniform in the operator breaks the circuit at the welding arc, the solenoid 8 releases its core, causing the pile resistance to be reduced to practically nothing which is equivalent to throwing the pile out ofcircuit. The end plates 32 and 37 may be coppe or they may be carboncopper plated, or they may be anyother suitable material;

sure adapted to maintain a in inverse proportion to W variations sub ect the increasing resistance of the pile and of the arc regulate the desired current flow to the amount provided by the location of springs 25 and 26 and the solenoid pull. This amount is subject to variation by the switch 17 and motor 20 as heretofore described. While the pile is normally in the electric circuit, its resistance is so low as to be negligible, and for all practical purposes at the moment when the terminals are brought into contact the pile might just as well be entirely out. of circuit The contact resistance is enough with the low voltage current employed, to prevent an objectionable flow of current. 7

Many of the features described may be varied without departing from the spirit of my invention.

What I claim is: a 1. In combination, in anarc welding system, a pair of welding terminals, one adapted to be manually operated to establish an arc, a variable resistance adapted to maintain a smooth current flow byivarying the resistance ofthe circuit, excluding the arc, in inverse proportion to the arc resistance, an electro-responsive device controlling said variations, intermediate means acted on by said electro-responsive device and acting upon said variable resistance to effect its resistance variations and means to render the action of said intermediate means sluggish. 2. In combination, in an arc welding system, a pair of welding terminals, one adapted to be manually operated to establish an arc, a variable resistance, variable by pressmooth current flow by varying the resistance of the circuit, excluding the arc, in inverse proportion to the arc resistance, an electro-responsive device controlling sai variations, 1ntermediate means acted on by said electroresponsive device and acting upon said va-' riable resistance to effect its resistance variaintermediate meansv slugglsh.

3. In combination, in an arc welding system, a'pair ofwelding terminals, one'adapted to be manually operated to establish an a variable resistance adapted to maintain a smooth current flow by varying the resistance of the circuit, excluding the arc, the arc resistance, an electro-responsive device controlling said tothe fullwelding current, intermediate means acted on by said electro-responsive device and acting upon said variable'resistance to-efiect its resistance variations and means to renderthe, action 01 said --intermediate means sluggish.

1 and 5 are brought jso - sistance of 4. In combination, in an arc Welding system, a pair of welding terminals, one adapted tobe manually operated to establish an arc, a variable resistance, adapted to maintain a smooth current flow by varying the resistance of the circuit, excluding the arc, in inverse proportion to the are resistance, an electro-responsive device controlling said variations in series with said resistance, intermediate means acted responsive device and acting upon said variable resistance to effect its resistance variations, and means to render the action of said intermediate means sluggish.

5. In combination, in anarc welding system, a pair of welding terminals, one adapted to be manually operated to establish an arc, a variable resistance adapted to maintain a smooth current flow by varying the resistance of the circuit, excluding the arc, in inverse proportion to the arc resistance, an electro-responsive device controlling said variations in series with said resistance and are, intermediate means acted on by said electro-responsive device and acting upon said variable resistance to effect its resistance variations and means to render the action of said intermediate means sluggish.

6. In combination, in an arc welding system, a pair of weldi g terminals, one adapted to be manually operated to establish an arc, a variable resistance adapted to maintain a smooth current flow by varying the rethe circuit, excluding the arc, 1n inverse proportion to the arc resistance, an electro-responsive device controlling said variations, intermediate means acted on by said ,electro-responsive device and acting uponsaid variable resistance to effect its resistance variations, means to vary the prosaid intermediatemeans yice and means to render the action of said intermediate means sluggish.

7. In combination, in an arc welding sys tem, a pair of welding terminals, one adapted to be manually operated to establish an arc, a variable resistance variable by pressure, adapted to maintain a smooth cur rent flow by varying the resistance of the circuit, excluding the are, in inverse proportion to the arc resistance, an electro-responsive device controlling said variations, in-

termediate means acted on by said electroresponsive device and acting upon said variable resistance to effect its resistance variations, means to vary the proportional effect of said intermediate means with relation to said electro-responsive device, and means to render the action of said intermediate means sluggish.

8. In combination, in an arc welding system, a pair of welding terminals, one adapted to be manually operated to establish an arc, a variable resistance adapted to on by said electro maintain a smooth current flow by' varying the resistance of the circuit, excluding the arc, in inverse proportion to the arc resistance, an electro-responsive device controlling said variations, subject to the full welding current, acted on by said electro-responsive device and acting upon said variable resistance to effect its resistance variations, means to vary the proportional effect of said intermediate means with relation sive device and means to render the action of said intermediate means sluggish.

9. In combination, in an arc welding system, a pair of Welding terminals, one adapted to be manually operated to establish an are, a variable resistance adapted to maintain a smooth current flow by varying the resistance the arc, in inverse proportion to the are resistance, an GlBCtI'OdGSPOIlSiVG device controlling said variations in series with said resistance and arc, intermediate means acted on by said electro-responsive device and acting upon said variable resistance to effect its resistance variations, means to vary the proportional effect of said intermediate means with relation to said electro-responsive device and means to render the action of said intermediate means sluggish.

10. In combination, in an arc welding system, a pair of Welding terminals, one adapted to be manually operated to establish an arc, a variable resistance adapted to maintain a smooth current flow by varying the resistance of the circuit, excluding the arc, in inverse proportion to the arc resistance, an electro-responsive device controlling said variations in series with said are, intermediate means acted on by said variable resistance to effect its resistance variations, means to vary the proportional eifect of said intermediate means with relation to said electro-responsive device and means to render the action of said intermediate means sluggish.

11. In combination, in an :arc welding system, a pair of welding terminals, one adapted to be manually operated to establish an are, a variable resistance adapted to maintain a smooth current flow by varying the resistance of the circuit, excluding the arc, in inverse proportion to the arc resistance, an electro-responsive device controlling said variations, intermediate means acted on by said solenoid and acting upon said variable resistance to effect its resistance variations, means to vary the proportional effect of said intermediate means with relation to said electro-responsive device, and a dash pot, coupled to said intermedlate means.

12. In combination, in an arc welding system, a pair of welding terminals, one

to said electro-respon intermediate means of the circuit, excluding adapted to be manually operated to establish an are, a variable resistance adapted to maintain a smooth current flow by varying the resistance of the circuit, excluding the arc, in inverse proportion to the are resistance, an electro-responsive device controlling said variations, intermediate means acted on by said electro-responsive device and acting upon said variable resistance to effect its resistance variations and a dash pot coupled to said intermediate means.

13. In combination, in .an arc welding system, a pair of welding terminals, one adapted to be manually. operated to establish an are, a variable resistance adapted to maintain a smooth current flow byvarying the resistance of the circuit, excluding the are, in inverse proportion to the are resistance, an electro-responsive device controlling said variations, intermediate means acted on by said electro-responsive device and acting upon said variable resistance to effect its resistance vari tions and a dash pot coupled to said intermediate means.

14. In an electric arc welding system, a metallic electrode adapted to supply a welding metal through the arc to the work, a source of current therefor, of such low potential as to avoid an objectionable initial rush of currentand spattering of metal, and means to increase the resistance of the welding circuit after the terminals are sufiiciently heated. j

15. In an electric arc welding system, a metallic electrode adapted to supply a welding metal through the arc to the work, a source of current therefor, of such low potential as to avoid an objectionable initial rush of current and spattering of metal, and means to increase the resistance of the welding circuit after the terminals are sufficiently heated, automatically operated by the establishment of the electric circuit through the welding terminals.

16. In an electric arc welding system, a metallic electrode adapted to supply a welding metal through the arc to the work, a source of current therefor, of such low potential as to avoid an objectionable initial rush of current and spattering of metal, means to increase the res'stance of the welding circuit after the terminalsare sufliciently .tential as to avoid heated, automatically operated. by'the establishment of the electric circuit through the welding terminals and time controlled means to retard the introduction of saidresistance 17. In an electric arc metallic electrode. adapted to supply a welding metal through the arc to the work, a source of current therefor, of such low poan objectionable initial rush of current and sp'attering Qf-metal, means to increase the resistance of the welding' circuit after the terminals are sufliciently heated, automatically operated by" the es- -ing metal across the arc to th welding system, a

a solenoid and carbon plle in series with the welding terminals.

18. In an electric arc welding system, a

metallic electrode adapted to supply a welding metal across the are to the work, a source of current therefor of such low potential as to avoid an. objectionable initial rush of current and spattering of metal, means to increasethe resistance of the welding circuit after the terminals are sufficiently heated and means to vary the amperage of said current at will."

19. In an electric .arc welding system, a metallic electrode adapted to supply a welde work, a source of current therefor of such low potential as to avoid an objectionable initial rush of current and spattering of metal, means to vary the amperage of said current at will under the control of the operator adapted to be carried by the operator to any location in reach from the said electrode and flexible means to enable the electrode to be carried at will to any work location desired. 20. In an electric arc welding system, a metallic electrode adapted to supply a welding metal across the are to thework, a source of'current therefor of such low potential as to avoid an objectionable initial rush of current and spattering of metal, means to in-' crease the resistance of the welding circuit after the terminals are sufficiently heated, automatically operated by .the establishment of the electric circuit through the'welding terminals and means to vary the amperage ing circuit after the terminals are sufliciently' heated, automatically operated by the establishment of the electric circuit acrossitne welding terminals and time controlled means to retard the introduction of said resistance into said welding circuit and means to vary.

the am erage of said current at will.

22. n an electric arcwelding system, a metallic electrode adapted to supply a welding metal across the arc to the work, a'source of currenttherefor of such low potential as to avoid-an objectionable-initial'rush of current and spattering' of metal and means to vary the amperage of said current at will under the control of the operator including a device adapted to be carried by the operator with the said electrode.

" .23. In an electric arc welding system, two

terminals, one of which is movable and such a degree as to prevent the drawing of adapted to draw an arc, and a low potena long, burning or slag forming arc.

tial current supply adapted to supply a 28. In combination, in an arc welding syscontinuously low potential current for the term, a source of current for welding, a pair purpose of establishing and maintaining of welding terminals, one of which is'mov- 7 the are between said terminals. able and between which an arc is adapted to 24. In an electric arc welding system, two be drawn, a resistance varying medium terminals, one of which is movable, and adapted to vary the resistance smoothly and adapted to draw an arc, a low potential gradually electro-responsive means acting 10 current supply adapted to supply a continuupon sai resistance varying medium to 7 ously low potential current for the purpose vary the resistance of said medium inversely of establishing and maintaining the are beand proportionally to the variations of the tween said terminals and means to. vary the arc resistance, the current supply for said amperage of said current at substantially a are having such a low potential as to avoid constant potential. the initial rush and spattering of metal In combination, in an arc welding when the resistance of said resistance varysystem, a source of current for welding, a ing medium is excluded from the circuit and pair of welding terminals, one of which is means to render the action of said resistance movable and between which an arc is varying medium sluggish.

adapted to be drawn, a resistance varying 29. In combination, in an arc welding medium adapted to vary the resistance system, a source of current for welding, a smoothly and gradually and electro-responpair of welding terminals, one of which is sive means acting upon said resistance var movable and between which an arc is adapting medium to vary the resistance of sa1d ed to be drawn, a resistance varying medium 5 medium inversely and proportionally to adapted to vary the resistance smoothly and the variations of the arc resistance, the curgradually, electro-responsive means acting rent supply for said are having such a low upon said resistance varying medium to potential as to avoid the initial rush and vary the resistance of said medium inversely spattering of metal when the resistance of and proportionally to the variations of the 30 said resistance varying medium'is excluded arc resistance, the potential of said source from the circuit. of current supply through said resistance 26. In combination, in an arc welding varying medium to said are being limited system, a source of current for welding, a in its potential to such a degree as to prepair of welding terminals, one of which is vent the drawing of a long, burning or slag 35 movable and between which an arc is adaptforming are and means to vary the proed to be drawn, a resistance varying medium 'portional I effect of said resistance varying adapted to vary the resistance smoothly and medium with relation to said 'electro-regradually and electro-responsive means actsponsive device. ing upon said resistance varying medium to 30. In combination, in an arc welding 40 vary the resistance of said medium inversely system, a source of current for welding, a

and proportionally to the variations of the pair f welding terminals, one of which is are resistance, the potential of said source movable and between which an arc is adaptof current supply thrpugh said resistance ed to be drawn, a resistance varying medium varying medium to said are being limited adapted to vary the resistance smoothly and 45 in its potential to such a degree as to pregradually electro-responsive means acting 11o vent the drawing of a long, burning or slag upon sai resistance varying medium to fOImIIIg vary the resistance of said medium inversely 27. In combinat on, 1n an arc welding and proportionally to .the variations of the system, a source of current for welding, a are resistance, the potential of said source 50 pair of weldlng terminals, one of which is of current supply through said resistance movable and between which an arc is adaptvarying medium to said are being limited ed to be drawn, a resistance varying medium in its potential to such a degree as to preadapted to vary the resistance smoothly and ventthe drawing of a long, burning or slag gradually and electro-responsive means actforming arc and means to vary the average 55 mg upon sa1d res stance a ying medlum to amperage of the current from said source vary the resistance of said medium inversely of current. and proportionally to the variations of-the 31. In combination, in an arc welding sysarc resistance, the current supply for said tern, a source of current for-welding, apair of are hav ng such a low potent al as to avoid welding terminals, one of which is m ble 60 the 1n1t1al rush and spattering of metal and between which an arc is adapted to be when the resistance of sa1d resistance varyrawn, a resistance varying medium adaptply through said resistance varying medium the resistance of said medium inversely and .in sa1d are being llmited 1n its potentlal to proportionallyto the variation of the are resistance, the potential of said source of current supply through said resistance varying medium to said are being limited in its potential to such a degree-as to prevent the drawing of a long, burning or slag forming arc and means to vary the average amperage of the current from said source of current, consisting of an electro-magnetic device and flexible electric connections combined with means adapted to be manually operated by the operator at the said average amperage.

32. In combination, in an arc welding systerm, a source of current for welding, a pair of welding terminals, one of which is movable and between which an arc is adapted to be drawn, a resistance varying medium,

' and electro-responsive means acting upon rent supply through degree as to able and between which said resistance varying the resistance of said medium inversely and proportionally to the variations of the arc resistance, the current supply for said are having such a low potential as to avoid the initial rush and spattering of metal when the resistance of said resistance varying medium is excluded from the circuit.

33. In combination, in an arc welding system, a source of current for welding, a pair of welding terminals, one of which is movan arc is adapted to be drawn, a resistance varying medium, and electro-responsive means acting upon said resistance varying medium to vary the resistance of said medium inversely and proportionally to the variations of the are resistance, the potential of said source of cursaid resistance varying being limited to such a prevent the drawing of a long, burning or slag forming arc.

' 34:- In combination, in an arc welding sysmedium to said are tem, a source of current for welding, a pair v of welding terminals, one of which is movable and between which an arc is adapted to be drawn, a resistance varying medium and electro-responsive means acting upon said resistance varying medium to vary the resistance of said medium inversely'and proportionally to the variations of the are resistance, the current supply for said are having such a low potential as to avoid the initial rush and spattering of metal when the resistance of, said resistance varying medium is excluded from the circuit, the potential of said source of current supply through said resistance varying medium to said arc being also limited to such a degree as to prevent the drawing of a long, burning or slag forming arc. w v

35. In combination, in an arc welding system, a source of current fonWelding, a pair of welding terminals, one of which is movable and between which an arc is adapted to be drawn, a resistance varying medium, electro-responsive means acting upon said rehis work to vary medium to vary- .ableand between which an sistance varying medium to vary the resistance of said medium inversely and proportionally to the variations of the arc resistance, the potential of said source of current supply through said resistance varying medium to said are being limited to such a degree as to prevent the drawing of a long, burning or slag forming arc and means to vary the average amperage of the current from said source of current.

36. In combination, in an arc welding system, a source of current for welding, a pair of welding terminals, one of which is movable and between which an arc is adapted to be drawn, a resistance varying medium in series with said are, electro-responsive means acting upon said resistance'varying medium to vary the resistance of said medium inversely and proportionally to the variations of the are resistance, the potential of said source of current supply sistance varying medium to said are being limited to such a degree as to preventthe drawing of a long,

are.

37 In combination, in an arc welding system, a source of current for welding, a pair of welding terminals, one of which is movarc is adaptedto be drawn, a resistance varying medium in series with said arc, electro-responsive means acting upon said resistance varying medium to vary the resistance of said medium inversely and proportionally to the variations of the arc resistance, the potential of said source of current supply through said resistance varying medium to said are being limited to such a degree as to prevent the drawing of a long, burning or slag forming arc.

38. In combination, in an arc welding system, a source of current'for welding, a pair of welding terminals, one of which is movable and between which an arc is adapted to be drawn, a resistance varying medium in series with said arc, electro-responsive means acting upon said resistance varying medium to vary the resistance of said medium inversely and proportionally to the variations of the arc resistance, the potential of said source of current supply through saidresistance varying medium to said are being limited to such a degree as slag forming arc, said electro-responsive device being located in series with said are.

39. In combination, in an arc welding system, a source ofcurrent pair of .welding terminals, one of which is movable and between which .an arc is. adapted 'to'be drawn, a resistance varying medium, electro-responsive means acting upon said resistance varying medium 'to vary the resistance ofsaid medium inversely and proportionally to the variations of the arc resistance, the potential of said source through said reburning or slag forming to prevent the drawing of a long, burning or for welding, a

through said resistance said are being limited to such a degree as to prevent the drawing of a long, burning or slag forming arc, said electro-responsive device being located in series with said resistance varying device.

40. In combination, in an arc welding system, a source of current for welding, a pair of welding terminals, one of which is movable and between which an arc is adapted to be drawn, a resistance varying medium in series with said are, electroresponsive means acting upon said resistance varying medium to vary the resistance of said medium inversely and proportionally to the variations of the arc resistance, the potential of said source of current supply of current supply varying medium to through said resistance varying medium to said are being limited to'such a degree as to prevent the drawing of along, burning, or slag forming arc, said electro-responsive device being located in series with said are and in series with said resistance varying device.

41. In combination, in an arc welding system, a,source of current for welding, a

, pair of welding terminals, one of which is to be drawn,

'pair of electrodes therefor, one of which is movable and between which an arc is adapted the potential of said source of current supply through said resistance varying medium to said are being limited to such a degree as to prevent the drawing of a long, burning or slag forming arc.

42. In combination, in an arc welding system, a source of current for welding, a pair of welding terminals, one of which. is movable and between which an arc is adapted to be drawn, the potential of said source of current supply through said resistance varying medium to said are being limited to such a. degree as to prevent the drawing of a long, burning or slag forming arc and means to vary the average amper-age of the currentfrom said source of current.

43. In an electric arc welding system, a manually'movable and adapted to draw and maintain an arc, a sourceof current therefor and means to limit the voltage of said current down to such a degree as will cause the arc to "break substantially before it reaches a temperature that will burn themetal.

In an electric arc welding system, a pair of electrodes therefor, one of which is metallic and manually movable and adapted to draw and maintain an arc, a source of current therefor and means to limit the voltage of. said current downto such a degree as will causethe arc'to break substantially before it reaches a temperature that will burn the meta i I a 45. In an electric arc welding system, :1.

pair of electrodes therefor, one of which is metallic and manually movable and adapted to draw and maintain an are, a source of current therefor and means to limit the voltage of said current down to such a degree as will cause the arc to break substantially before it reaches a temperature that will burn the metal, and means to vary the amperage of said current at will.

46. In an electric arc welding system, two metallic electrodes, one consisting of work, a flexible connection between the permanent stationary conductor terminal and said electrode, the other electrode adapted to be manually manipulated by an operator for the purpose of drawing and maintaining an arc, means to continuously limit the current supplied to said electrodes down to such a degree as will cause the arc to break before reaching a metal burning and slag forming temperature, flexible means connecting said electrode with a permanent conductor terminal, and means to vary the amperage of the current including the variable resistance device located near said terminals.

47. In an electric arc welding system, two metallic electrodes, one consisting of work, a flexible connection between the permanent stationary conductor terminal and said electrode, the other electrode adapted to be manually manipulated by an operator for the purpose of drawing and'maintaining an arc, means to continuously limit the cur rent supplied to said electrodes down to such a degree as will cause the arc to break before reaching a metal burning and slag forming temperature, flexible means connecting said electrode with a permanent conductor terminal, means-to vary the amperage of the current including the variable resistance device located near said terminals, and suitable switching apparatus adapted to be mounted by the operator to a distance and flexible connections between said switching apparatus and said variable resistance device.

48. In an electric welding system, two electrodes, one of which is manually operable and, adapted to maintain an arc, automatic'means to smoothly vary the resistance in said system to substantially compensate for the fluctuations of resistance in said arc, and means to dampen'the said automatic means to prevent mechanical interference with said compensation.

Signed at New York in the county of New York and State of New York this 13th day of April, A. D. 1915.

DAVID H. WILSON. Witnesses: 

